The invention relates to crystalline modifications of (1R,2R)-3-(3-dimethylamino-1-ethyl-2-methyl-propyl)-phenol, pharmaceutical compositions which contain these modifications, and the use thereof.
(1R,2R)-3-(3-dimethylamino-1-ethyl-2-methyl-propyl)-phenol is a synthetic analgesic which is used for the treatment of severe to very severe, acute and chronic pains. The compound can in this case be used in the form of the free base thereof or in the form of pharmaceutically acceptable salts and solvates. The production of the compound and the salts thereof is known from U.S. Pat. No. 6,248,737 (=EP 693,475), the compound normally being obtained in the form of a salt thereof, for example in the form of the hydrochloride thereof.